The subject matter disclosed herein relates generally to gasification power plants. More specifically, the subject disclosure relates to air separation plants for use in power production.
Typical gasification power plants use oxygen to convert a feedstock, for example, coal into a fuel gas for combustion in a gas turbine to produce electrical power via a generator connected thereto. In an integrated gasification power plant, the air from which the oxygen is separated is supplied from the gas turbine compressor thus improving plant efficiency and reducing cost. Air is compressed in the compressor of the gas turbine, and oxygen is produced from the compressed air by separating the oxygen from other constituents of the compressed air in an air separation unit. One type of air separation unit commonly used is a membrane-based air separation unit. In a membrane-based separation unit, air separation occurs at temperatures above about 1400 F., typically in the range of about 1400 F. to about 1600 F. Compressed air from the gas turbine compressor, however, is available in the range of about 600 F. to about 1000 F. Thus, the compressed air is heated via a heat exchanger or fuel heater to raise the temperature to the necessary 1400 F. to 1600 F. for utilization in the air separation unit. Utilization of this heat exchanger adds additional cost and requires additional fuel to operate.